Implement needs_commit for Mercurial

Issue #511
Signed-off-by: Michal Čihař <michal@cihar.com>

weblate/trans/tests/test_vcs.py

@@ -254,9 +254,6 @@ class VCSHgTest(VCSGitTest):
     def test_merge(self):
         return
 
-    def test_needs_commit(self):
-        return
-
     def test_needs_merge(self):
         return
 

weblate/trans/vcs.py

@@ -643,13 +643,11 @@ class HgRepository(Repository):
     def needs_commit(self, filename=None):
         """
         Checks whether repository needs commit.
-
-        TODO
         """
         if filename is None:
-            status = self.execute(['status', '--porcelain'])
+            status = self.execute(['status'])
         else:
-            status = self.execute(['status', '--porcelain', '--', filename])
+            status = self.execute(['status', '--', filename])
         return status != ''
 
     def get_revision_info(self, revision):